Recovery of metal from electrolyte using electrolysis is in practice by many industries like plating, mining and metal finishing. Recovery of copper from the solutions containing copper metal in the form of ions is well known process (JP2004244663 (A), WO2009090774 (A1)). Present invention relate about study of electrolysis as a main reaction in the copper-chlorine cycle in which copper is formed cathode and cupric chloride get produced on anode.
An electrolytic apparatus and process for the online regeneration of acid cupric chloride etching baths used in printed circuit board fabrication is described. The copper metal etched into the system is completely removed. Graphite and/or carbon material is used as cathode and anode. Micro porous separator is used for separation of anolyte and catholyte solution (US005421966A).
US2008/0283390A1 describes a method for electrolysis of cuprous chloride to produce copper powder and cupric chloride for Cu—Cl thermochemical cycle. Dense graphite electrodes are used as working electrodes as anode and cathode. Anion exchange membrane made from poly and polyethylenimine cross-linked is used as a separating medium. The electrodes are designed in the form of channels rib manner. The electrolyte flows through the respective channels. The main problem is the removal of copper powder formed during the electrolysis. The different additives have been used to enhance the solubility of CuCl. To increase the conductivity the solution was seeded with carbon black material.
US2010/051469A1 used electrochemical cell for production of hydrogen gas at cathode and cupric chloride at anode electrode from the electrolysis of cuprous chloride and HCl. The anolyte and catholyte used are cuprous chloride in hydrochloric acid and water respectively. Cation exchange membrane is used as separating medium between the anode and cathode compartment.
One of the main challenges of this process is to achieve high efficiency during the electrolysis of CuCl. Main difficulty in the electrolysis of cuprous chloride to copper powder formation and cupric chloride formation is removal of copper powder formed on the cathode electrode and formation of cupric chloride by competing reaction between dissolved oxygen and cuprous chloride in the presence of HCl as2HCl+2CuCl+0.5O2→2CuCl2+H2O
With increase in HCl concentration, rate of formation of undesired anionic species like CuCl2−, CuCl32− increases. With decrease in concentration of HCl, there is precipitation of cuprous chloride occur in the cell.